add buildrump.sh as a submodule

(mostly for the benefit of Travis CI build tests)
Travis CI support

first attempt ...
export env in "script" instead of creating an "env" matrix
add travis build status stamp

[ci skip]
no need to run buildrump.sh tests here
join lines broken by pasto
update buildrump.sh URL
also make the URL in previous an actual URL
add a LICENSE file
add AUTHORS file